Methods and apparatus related to a unitary fork brace

ABSTRACT

Embodiments of a fork brace for a bicycle are disclosed herein. In one aspect, a brace portion is integrally formed along with two tubular fork members and an overlay fits in a mating relationship with the brace portion to create a unitary, tubular brace.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and claims priority to theco-pending U.S. patent application Ser. No. 14/412,199 filed on Mar. 26,2009, entitled “METHODS AND APPARATUS RELATED TO A UNITARY FORK BRACE”by Mario Galasso et al., assigned to the assignee of the presentapplication, having Attorney Docket No. FOXF/0023, and is herebyincorporated by reference in its entirety.

The application Ser. No. 12/412,199 claims the benefit of and claimspriority to the U.S. Provisional Patent Application Ser. No. 61/039,497,filed Mar. 26, 2008, entitled “METHODS AND APPARATUS FOR STRUCTURALREINFORCEMENT OF VEHICLE SUSPENSION” by Mario Galasso et al., assignedto the assignee of the present application, having Attorney Docket No.FOXF/0023L, and is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

Embodiments of the invention generally relate to methods and apparatusfor use in vehicle suspension. Particular embodiments of the inventionrelate to methods and apparatus useful for structural reinforcement ofsuspension components, more particularly, reinforcement of front forksusing a brace comprising a base portion and an overlay portion toproduce a rigid structural unit.

BACKGROUND OF THE INVENTION

Vehicle suspension systems typically include structures that must resistforces tending to twist and/or bend those structures. Further, it isdesirable that such structures be maintained in position relative to oneanother. That often means that the structures and/or their connection toone another need to be suitably reinforced. In many applications, it isalso desirable to minimize the weight of vehicle components, includingsuspension components, in order to increase performance. What is neededis a structural reinforcement that is lightweight yet suitably rigid inapplication. Front forks for bicycles are an example of a componentrequiring rigidity in order to operate effectively. Each fork isconnected at a lower end to an axle and at an upper end to a fork crown.However, as fork travel has been extended, an additional reinforcementhas been added in the form of a fork brace extending between the lowerfork legs of the front fork suspension unit. FIG. 1 is a Figure of afork 10 and illustrates the brace 15 extending between the fork legs 20,25. In the fork of FIG. 1, the fork legs are tubular and the brace isintegrally formed between them in order to provide rigidity and keep theforks parallel to one another. The purpose of the brace 15 is to helpmaintain the fork legs in a substantially parallel relationship whilethey are being subjected to rider and terrain induced disparate loads.

FIG. 2 is a rear view of an integral brace 15 formed between fork legs20, 25 and illustrates reinforcement webs 35 used in the brace. Becausethe fork assembly, including the brace portion is typically cast in onepiece, manufacturing limitations prevent the brace from being formedinto a tubular shape along with the two tubular forks legs. Instead, thebrace 15 has a hollow back portion 30 that includes integral, web-likestructures 35. The result is a reasonably rigid brace having additionalweight due to the extra webs required to impart rigidity and having nocontoured, attractive appearance when viewed from the rear. Such a bracedoes therefore fail to maximize rigidity between fork leg members whileminimizing extra weight associated with such support.

There is a need therefore, for a fork brace that makes use of a tubularcross section even when a portion of the brace is integrally formed withtubular fork legs. There is yet a further need for a fork brace thatprovides a more contoured, attractive appearance from all angles.

DRAWINGS

FIG. 1 shows a fork assembly with a brace between the fork legs.

FIG. 2 is a rear view of a brace and illustrates structuralreinforcement of the brace.

FIG. 3 is a front view of the fork assembly with a rear portion of abrace integrally formed therebetween.

FIG. 4 is a rear view of a fork assembly including an embodiment of thebrace.

FIG. 5 is a top view of an overlay portion.

FIG. 6 is a rear view of an overlay portion showing the undersidethereof.

FIG. 7 shows the rear portion and overlay portion mated together to formthe brace.

SUMMARY OF THE INVENTION

Embodiments of a fork brace for a bicycle are disclosed herein. In oneaspect, a brace portion is integrally formed along with two tubular forkmembers and an overlay fits in a mating relationship with the braceportion to create a unitary, tubular brace.

DESCRIPTION OF A PREFERRED EMBODIMENT

In one embodiment a two wheeled vehicle such as a bicycle or motorcycleincludes a suspension structure comprising a pair of lower, frontsuspension fork legs connected by a brace. FIG. 3 is a front viewshowing the front fork assembly 100 with a portion 110 of a brace 300integrally formed between the fork legs. In the embodiment shown, thebrace portion 110 is formed at the same time as the fork legs and of thesame metallic material and includes a surface 125 and sides 130extending around the perimeter of the surface 125. In another embodimentthe brace portion 110 may be formed separately from the fork legs,and/or of a different material, and attached thereto. Because it isdesigned to be used with an overlay (e.g. 200), the portion 110 isformed with an essentially “open” front. The portion 110 also includes alip 135 formed around its outer perimeter to permit the overlay to beseated, as will be described. Also included are reinforcement members140 extending from the rear surface past a top edge of the sides 130 andoutwardly corresponding to an interior dimension of the assembled brace(with overlay) to add additional rigidity and/or facilitate a connectionbetween the portion and the overlay. In the embodiment shown, a threadedboss 145 is formed in the rear portion to receive a threaded fastener.FIG. 4 is a rear view of the fork assembly of FIG. 3 and shows a smooth,contoured rear surface 101 of the portion 110.

The portion 110 of the brace 300 and the lower fork legs are preferablymade of castable material like magnesium, aluminum or titanium but canbe made of fiber reinforced polymer (e.g. carbon and/or glass reinforcedepoxy or PEEK or other polyarylenes) or any other suitable structuralmaterial providing a suitably high level of strength, stiffness andimpact resistance or any suitable combination thereof.

FIG. 5 is a front view of an overlay 200 that is designed to fit in amating relationship over the portion 110 of the brace 300 to create aunitary, structural brace assembly with a substantially tubularcross-section. While the brace 300 is described as having a “tubular”cross section, it is understood that the term “tubular” in thisspecification relates to any shape that includes a substantially closedor boxed cross-section and is not limited to any particular tubularshape.

FIG. 6 is a rear view of the overlay portion of FIG. 5 showing theunderside thereof. As illustrated by the Figures, the overlay 200 isformed with sides 210 constructed and arranged to fit over the sides 130of the rear portion 110 and having a thickness that, upon assembly,abuts the lower lip 135 that extends around the perimeter of portion110. In cross section, the overlay 200 has a semi-triangular shape withboth sides 210 intersecting to form a crest 215 that provides stiffnessand strength to the overlay, especially when it is combined with therear portion 110. In the embodiment shown, the overlay 200 includescontoured ends 220 that mate with similar formations 112 formed in therear portion and on the front of the lower fork legs (see FIG. 3). Alsoincluded is a formed aperture 142 for receiving a threaded or otherfastener (e.g., screw) to facilitate the connection of the overlay tothe threaded boss 145 formed in the portion.

The overlay is preferably made of a different material than the forkassembly and in one embodiment is preferably moldable. Optionally theoverlay may be made by vacuum bagging, pressing, lay up, in mold lay up,casting or other suitable manufacturing method or combination thereof.While the overlay may be made of a metallic material like magnesium,aluminum, or titanium, it preferably comprises fiber reinforced polymer(e.g. carbon or glass reinforced thermoset or thermoplastic polymer suchas for example epoxy or Polyetheretherketone (“PEEK”) respectively) orany other suitable structural material, reinforcement or combinationthereof. The carbon fiber/epoxy of the overlay may be prepreg fabric andmay consist of high or low modulus carbon fiber or any suitablecombination thereof. The carbon fiber may be in a woven fabric form, matfabric form, may be preferentially oriented using unidirectional fiberreinforcement in anticipation of greater stresses in given orientationsor may comprise any suitable combination of the foregoing.

FIG. 7 shows the rear portion 110 and overlay 200 mated together to formthe completed brace 300. As shown, the lower edge of the overlay sides210 fit on the lower lip 135 of the rear portion to make a substantiallycontinuous, supporting connection therebetween. Additionally, thecontoured interior surface of the overlay sides 210 (visible in FIG. 6,the rear view of the overlay 200) are at least partially supported bythe sloped outer surface of sides 130 of the rear portion 110 (visiblein FIG. 3, rear view of the fork assembly). In one embodiment eachreinforcement 140 extending from the rear surface 125 contacts an innersurface of the overlay and provides additional support for the overlayand the assembly.

In one embodiment, the rear portion 110 and overlay 200 are gluedtogether with an adhesive material applied around the perimeter of thesides 130 and where the overlay sides 210 meet lip 135 in order toprovide a continuous, adhesive connection between both portions of thebrace assembly 300. Additionally, the outer edge of each reinforcement140 is coated with adhesive to create an adhesive arrangement at eachpoint where the reinforcement 140 contacts the inner surface of theoverlay 200. Adhesives may include epoxies, cyanoacrylates or othersuitable adhesive materials. In one embodiment, the overlay 200 and therear portion 110 both comprise metal and the assembly is welded. In oneembodiment the overlay 200 and the rear portion 110 both comprisethermoplastic and the assembly is thermoplastic welded. In oneembodiment both the rear portion 110 and the overlay 200 compriseparticulate metal and the assembly is sintered. In one embodiment theoverlay 200 is bonded to the rear portion using a heat activated bondingagent (e.g. polar molecule) suitable for action between the overlaymaterial and the rear portion material. Depending on the composition ofthe overlay 200 and the rear portion 110 any suitable method or materialmay be used for assembling the brace 300. Also visible in FIG. 7 isaperture 142 leading to threaded boss 145. In this embodiment, theconnection between the rear portion and overlay can be furtherreinforced with a threaded member (such as for example a headed machinescrew).

In one embodiment the connection between the overlay 200 and the rearportion 110 is mechanical. In one embodiment the connection comprisesrivets. In one embodiment, rather than mating directly along a lip 135of the rear portion 110, the rear portion may include a channel (notshown) formed around its base in which case the lower edge of theoverlay 200 fits within the channel. The channel may have a widthslightly smaller than the thickness of edge (and optionally edge 210 mayinclude an “arrow” shaped cross section where channel includes aninverse “arrow” shaped cross section) so that the fit overlaps and/orinterferes. Alternatively, the channel may be formed along the loweredge of the overlay 200 and a lip formed around the rear portion 110could extend into the channel of the overlay 200. Any suitable overlapor blend between the overlay 200 and the rear portion 110 may be used tofacilitate a structural connection between the two components.Optionally the overlay 200 may be joined to the rear portion byinterference fit, pressure fit, sonic welding or any other means knownin the art or connecting similar materials to form a robust connectionthere between. Optionally, a void formed in the interior of the tubularbrace may be filled with a light weight, structural foam. Such formwould provide additional structural support and may also serve toconnect (e.g. adhere) the overlay 200 to the rear portion 110.

As illustrated in FIG. 7, when fitted together, the overlay and the baseare structurally connected to form a unitary, tubular brace between thefork legs that is visually pleasing and/or aerodynamically efficientwhen viewed from the front or the rear. While not illustrated, therelative positions of the brace portion and the overlay could bereversed whereby the brace portion is disposed at a front end of thefork assembly with an “open” rear for receiving the overlay. The resultis, in any case, a unitary, tubular brace with a portion thereofintegrally formed between two fork legs.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the scope thereof, and the scope thereof is determined bythe claims that follow.

What we claim is:
 1. A method for reinforcing a suspension componentcomprising: fabricating a brace portion having a surface and at leastone reinforcement member extending from the surface and having at leastone structural, tubular member formed at each end thereof; fabricatingan overlay, the overlay configured to cover an open front of the braceportion; and attaching the overlay to the brace portion to form areinforced suspension component.
 2. The method of claim 1, wherein thereinforced suspension component is tubular in cross section.
 3. Themethod of claim 1, wherein the attaching includes the use of adhesivebetween at least one contact area between the first component and theoverlay.
 4. The method of claim 1, wherein the attaching includes theuse of at least one mechanical fastener between the first component andthe overlay.